Public Wide Area Networks are growing rapidly in popularity. A “public network” is a network operated by common carriers or telecommunications administrations for the provision of circuit switched, packet switched, and leased-line circuits in the public. The Internet and World Wide Web are common examples of public networks. In contrast, a “private network” refers to a network owned by an end user organization and/or a network comprising dedicated circuits leased by an end user organization from one or more public carriers. An enterprise network is a common example of a private network.
Each year more users use the Internet for a variety of purposes, including electronic commerce, interpersonal communications, information acquisition, and the like. An integral part of this rise in Internet popularity is the Internet Service Provider or ISP. The ISP is a vendor that provides access for customers, whether companies or private individuals, to the Internet and World Wide Web. The ISP also typically provides a core group of Internet utilities and services, like E-mail, News Group Readers, and, sometimes, weather reports and local restaurant reviews. The user typically reaches his ISP by either dialing-up with their own computer, modem and phone line, or over a dedicated line, such as a Digital Subscriber Line or DSL, installed by a telephone company. An ISP is also called a TSP, for Telecommunications Service Provider, and an ITSP for Internet Telephony Service Provider.
Typically the ISP provides different types of services (e.g., gold, silver and bronze) to enterprise customers with an expense charging model. The enterprise network administrator generally administers a policy server and/or Access Control Lists (ACL) (a set of rules for filtering traffic based on packet header variables such as IP address, transport protocol, and port number) on the enterprise edge egress router or uses traffic shaping devices, such as the Packet Shaper™ by Packeteer™ and QoSWorks™ by Sitara Networks™ to comply with the various Service Level Agreements (SLA's) between the ISP and its various customers. “Traffic shaping” refers to congestion and management procedures in which data traffic is regulated to conform to a specified, desirable behavior pattern, such as reduction or elimination of excessive traffic bursts.
An SLA is an agreement between a user and a service provider, defining the nature of the service to be provided and establishing a set of metrics or measurements to be used to measure the level of service provided measured against the agreed level of service. Such service levels might include provisioning, average availability, restoration times for outages, availability, average and maximum periods of outage, average and maximum response times, minimum bandwidth level, minimum Quality of Service or QoS parameters, delivery rates (e.g., average through minimum throughput, etc.). Residential users having only modem connections rather than DSL connections typically do not have an SLA.
The ISP may use Policy-Based Routing (PBR) (which routes packets pursuant to nontechnical policy considerations, such as permissions and reciprocal business contacts between and among backbone carriers, ISP's, and Internet Access Providers) and/or Constraints-Based Routing (CBR) (which routes packets based on technical considerations, such as selecting a route complying with Quality of Service or QoS requirements (e.g., packet delay, jitter, and/or packet loss)). The routing protocol is often associated with label switching protocols, such as Frame Relay, Asynchronous Transfer Mode or ATM, or MultiProtocol Label Switching or MPLS (which uses packet labeling to expedite routing), and uses the IP packet header Type of Service or TOS byte, to provision the network for different types of services.
Notwithstanding the relatively high level of sophistication of ISP's, the increased usage of the Internet has caused increased levels of congestion of scarce Internet resources and has required the implementation of protocols to provide circuit-switched-like QoS levels to Internet users for certain demanding applications. An example is the Resource ReSerVation Protocol or RSVP. RSVP supports resource reservations through networks of varying topologies and media. Through RSVP, a user's QoS requests are propagated to all routers along the path, allowing the network to reconfigure itself (at all network levels) to meet the desired level of service. The RSVP protocol engages network resources by establishing flows throughout the network. A “flow” is a network path associated with one or more senders, one or more receivers, and a certain QoS. A sending host wishing to send data that requires a certain QoS will send Unicast “path” messages toward the intended recipients. The path messages, which describe the bandwidth requirements and relevant parameters of the data to be sent, are propagated to all intermediate routers along the path. A receiving host, interested in the particular data, will confirm the flow (and the network path) by sending “reserve” messages through the network, describing the bandwidth characteristics of data it wishes to receive from the sender. As these reserve messages propagate back toward the sender, intermediate routers, based on bandwidth capacity, decide whether or not to accept the proposed reservation and commit resources. If an affirmative decision is made, the resources are committed and reserve messages are propagated to the next hop on the path from source to destination. For a premium price, RSVP enables certain traffic, such as a videoconference, to be delivered before e-mail. This is contrary to the historic configuration of the Internet in which all traffic moves on a first-come-first-served basis and is charged at a flat rate. RSVP, however, is not scalable, and it is not practical to enable RSVP on all of the routers end-to-end.
Currently, the Internet does not provide small business and residential users with the opportunity to use the high-speed network links in the ISP network dynamically for their applications. Such users do not generally have, or can afford to have, policy servers, edge routers, or traffic shapers so they commonly cannot make use of or afford the different QoS service levels provided by the ISP. ISP's do not provide (push) the network occupancy/availability of varying levels of bandwidth/QoS available in their network to the end users when they logon. Therefore, such users cannot avail themselves of higher speeds even when the ISP network is not loaded (off peak). In contrast to the overuse of resources when peak Internet traffic levels are experienced, this incapability of ISP's causes under use (or wastage) of resources when off-peak Internet traffic levels are experienced.